Refueling assemblies for engines have been developed to enable an operator to quickly and easily refill a fuel tank. Refueling assemblies may include a fuel cap. However, the cap may become lost, misplaced, etc., during refueling operation. Moreover, the evaporative vehicle emissions may be increased when a cap is used, due to the fuel vapor loss that occurs when the cap is removed.
Cap-less refueling assemblies have been developed to reduce evaporative emissions as well as simplify the refueling process. The cap-less refueling assembly may include a spring loaded interior lid to enable the refueling assembly to be sealed when a fuel nozzle is removed from the assembly.
However, the Inventors have recognized several drawbacks with this type of refueling assembly. Firstly, premature shut-off of the fuel nozzle during refueling may occur due to the pressure differential which develops in the refueling assembly. Fuel fill system shut off is historically based on sensing a pressure differential: P2 (nozzle shut-off pressure during refueling)−P1 (fuel tank peak fill pressure). Moreover, air entrapment in the refueling assembly may occur during refueling. Additionally, carbon canister loading may be increased. Moreover, due to the geometric configuration of various flow guides in the refueling assembly, the pressure differential in the fuel tank over the entire refueling process is decreased, thereby increasing the refueling duration.
To solve at least some of the aforementioned disadvantages a refueling assembly of an engine is provided. The refueling assembly includes a housing, a door positioned within the housing and a flow guide positioned within the housing and downstream of the door including an inlet in fluidic communication with the door, an outlet to flow fuel into a downstream filler pipe in fluidic communication with a fuel tank during a refueling operation, a planar nozzle seating section receiving a fuel nozzle during the refueling operation, and a contraction section positioned downstream of the planar nozzle seating section. The geometry of the flow guide in this example reduces entrained air, where entrained air alters the pressure differential that signals shut off. Thus, minimizing entrained air optimizes this pressure differential and limits premature shut-off.
The planar nozzle seating section enables the movement of the fuel nozzle to be reduced during refueling, thereby decreasing local pressure sensitivity and decreasing the likelihood of premature shut-off of the fuel nozzle during a refueling operation. The flow guide may also include an extension section, having a constant inner diameter, positioned downstream of the contraction section. The extension section enables the likelihood of air entrapment in the refueling assembly to be reduced during a refueling operation. Additionally, the contraction section may be conical. The conical geometry enables the localized pressure sensitivity in the flow guide to be reduced. As a result, the likelihood of premature shut-off of the fuel nozzle during refueling may be reduced.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.
FIGS. 2-8 are drawn approximately to scale.